title: Peptaibols, tetramic acid derivatives, isocoumarins, and sesquiterpenes from a Bionectria sp. (MSX 47401).
abstract: An extract of the filamentous fungus Bionectria sp. (MSX 47401) showed both promising cytotoxic activity (>90% inhibition of H460 cell growth at 20 μg/mL) and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). A bioactivity-directed fractionation study yielded one new peptaibol (1) and one new tetramic acid derivative (2), and the fungus biosynthesized diverse secondary metabolites with mannose-derived units. Five known compounds were also isolated: clonostachin (3), virgineone (4), virgineone aglycone (5), AGI-7 (6), and 5,6-dihydroxybisabolol (7). Compounds 5 and 7 have not been described previously from natural sources. Compound 1 represents the second member of the peptaibol structural class that contains an ester-linked sugar alcohol (mannitol) instead of an amide-linked amino alcohol, and peptaibols and tetramic acid derivatives have not been isolated previously from the same fungus. The structures of the new compounds were elucidated primarily by high-field NMR (950 and 700 MHz), HRESIMS/MS, and chemical degradations (Marfey's analysis). All compounds (except 6) were examined for antibacterial and antifungal activities. Compounds 2, 4, and 5 showed antimicrobial activity against S. aureus and several MRSA isolates.
authors.affiliation: Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Figueroa
authors.forename: Huzefa
authors.initials: H
authors.lastname: Raja
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Falkinham
authors.forename: Audrey F
authors.initials: AF
authors.lastname: Adcock
authors.forename: David J
authors.initials: DJ
authors.lastname: Kroll
authors.forename: Mansukh C
authors.initials: MC
authors.lastname: Wani
authors.forename: Cedric J
authors.initials: CJ
authors.lastname: Pearce
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Oberlies
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification; D006801:Humans; D006999:Hypocreales / Q000737:chemistry*; D049934:Isocoumarins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D054848:Peptaibols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification; D011760:Pyrrolidinones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D006027:Glycosides; D049934:Isocoumarins; D054848:Peptaibols; D010455:Peptides; D011760:Pyrrolidinones; D012717:Sesquiterpenes; C105477:clonostachin; C535097:virgineone; C009435:tetramic acid